Replacing transistors on a Sanyo...

jow

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This will be my first time doing so. Anything I should know, look out for, fear, weep at, slob about, before hand? Is this simple for a n00b like myself? I have capped 3 Sanyo's in my day, but never replaced transistors.
 
3 legs to unsolder, make sure you put it in the same way the old one came out (orientation-wise), if it is mounted to a heat sink or wall check to see if it needs and insulator between it and what it mounts to (it sometimes sticks to the old transistor if there is one)...
 
I don't even think those have heatsinks. at least that's what I recall from the last few I capped, cause I had colors dropping out on them post-capping, had to reflow all the transistors.

very very simple procedure though if you have desoldering capability, otherwise it'll take a little finesse to get them out with a regular iron, at which point you'd be best to cut the legs, and pull them individually with needlenose pliers while heating the solder joint. I use dental picks to clear out holes, they're extremely handy to have around. then you can install the new transistor. depending on the hole alignment, you may have to throw a bend in the middle leg of the transistor, but this is a very easy procedure.
 
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very very simple procedure though if you have desoldering capability, otherwise it'll take a little finesse to get them out with a regular iron, at which point you'd be best to cut the legs, and pull them individually with needlenose pliers while heating the solder joint. I use dental picks to clear out holes, they're extremely handy to have around. then you can install the new transistor. depending on the hole alignment, you may have to throw a bend in the middle leg of the transistor, but this is a very easy procedure.

Sweet, good to know. I have a decent desoldering iron so I should be good to go. Thanks for all the info!
 
Those were easy enough to replace...

...but when everything was hooked back up, I got sparks/smoke on the main DK PCB? WTF?

I immedidatley shut her off, unplugged the PCB, and turned it back on. No neck glow, no nothing. Just a buzzing sound from the PS.

FML.
 
There is a connector on the audio board that can be swapped with another plug accidentally. I can't remember the plug ID at the moment, I wanna say it's JB or JF or something like that. (haven't rebuilt a Sanyo in a while) anyway as far as I know this is the only thing that will blow out the audio section of a DK or DK Jr board.
 
they're JB and JC if I recall.

they're labeled as such too.

so, yeah. I don't recall what goes under that scenario, the audio board definitely gets nuked. probably shot something back through the audio cable at your DK board.

unfortunate. I should've mentioned this, but I wasn't expecting you to pull the entire chassis out (which is something I try to avoid if I can in non-capping situations cause they're such a pain in the ass to remove), I've done this to the neckboard while it's still hooked into the tube.
 
Yep, I'm an idiot. I had JB and JC backwards. FML.

Still have vert collapse even after replacing the transistors. I didn't have a full cap kit handy, so I guess I'll do that next? The Sanyo flowchart said to suspect faulty TR402 and TR403 so I only replaced those. No dice.

Greg - service switch is off. When on, the line down the middle of the monitor is white. When off, the line is a reddish orange color.
 
when the vertical output transistors fried they very likely took out the fusable resistor that supplies the voltage to them. Check the circuit and/or measure on the legs of the vert transistors for voltage.

PS don't leave the unit running for long in this condition and maybe also turn down the screen pot or you can damage the tube
 
when the vertical output transistors fried they very likely took out the fusable resistor that supplies the voltage to them.

When would this have happened? The original transistors looked fine, I just replaced them to see if that was it. The damage I caused was from the audio amp being hooked up backwards, and it fried the audio section of the game PCB. Nothing on the monitor chassis happened?
 
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